Looks to me that the nose cone makes the major difference.

Come on Cervelo, let's go full fairings!!

It'll be interesting to hear more about that tunnel testing and the aero design once Mark Cote gets back here.
I wonder though if a UCI illegal bike with Shiv TT geometry might test a bit better than the higher tri Shiv? Does the graph compare bikes of the same fit, and if so is that fit more "natural" on one or other of the bikes?

From the graphs of the 3 Shiv models though, you could draw the conclusion that any general reductions in drag from frame design will now be limited....

looks to me like the nosecone hurts at low yaw, helps at high yaw

It may very well be a net win in most conditions but not a huge one.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

We all know UCI illegal components such as aerobars (think Ventus) are superior in their aerodynamics - though said benefits are arguable marginable.
UCI illegal frames has been historically quick (think Zipp frames, etc).
Looking at the drag on these three Shivs in a triathlon scope, I would be going for the nosecone Shiv or the 2012 Shiv (tri) as the drag in crosswinds appears lower. Given the new Shiv Comp shares these numbers, it makes for an awesome $3k bike/

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Coaching - Future Endurance

since i've been staring at this chart now several times now. i have started to wonder why the driveside has less drag than the non-driveside? am i not understanding the yaw angles correctly? is that drag on the driveside with it 'quartering into' or quartering away' from the wind?


then i'm looking at the tt with vs without the nose cone and i'm seeing less drag number for the one without? (for 0* it shows ~1-2watts differece) seems like that's a little backwards for some reason?

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Tim

i had similar thoughts, but more from a PR perspective.

The results of this new bike are not that impressive. certainly not mind-blowing. if I were in the UCI, I'd couple that with the previously stated opinions of manufacturers like Cervelo and i'd say, "see? we're not stifling innovation. our efforts to protect the spirit of the sport have worked and clearly with very little impact to performance."

the other thought was more marketing: if this is Specialized best effort after saying "to hell with the UCI specs", is this really a best effort? this is it? the UCI constraints are limited to the size of the down-tube and otherwise they haven't held the engineers back at all? where's the shrouded chainring, where's the chain running thru the chain stays, where's a major leap of some sort? it makes me wonder if the manufacturers are subtly acknowledging that they need to build the most innovative bike that will still sell.

Think about what the nosecone is doing.
It improves the shape of the front brake

but increases frontal area.

You will see this pattern repeated in tunnel data all over the place - the integrated front end bikes, like the speed concept, have worse drag at low yaw than the P4

the nosecone shiv has worse drag at low yaw than the non nosecone shiv

etc

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

it doesn't really increase the frontal are does it?

from the front it would seem the size of the bike is the same...... is it some Cda type math problem going on there?

1-2watts in my book is not a matter of great concern as i'm sure there is somewhere else i could shave that effort off, not to mention the likelihood of 0* yaw angle in the real world.

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Tim

But your premise is off by a bit. Specialized has said that building the most aero frame wasn't the goal for the Shiv TT. It was to build the best frame for the typical triathlete. To that end it uses all standard components, is easy to wrench, fits easier in a standard bike case, etc.

That they came almost in a dead heat with a bike that is also non UCI nosecone shiv) , but much more problematic from the above standpoints is an accomplishment. The other benefit is that its cheaper to manufacture without all of the proprietary stuff and cheaper.

Styrrell

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Styrrell

Have you looked at the front end of a Speed Concept 9 series? There's not more frontal area than a P4.

Trek has said that they design their bikes to be optimal at a certain yaw angle. Cervelo has said the same thing. The Canadians, however, believe in a much lower yaw sweep, while in Wisconsin they believe a higher yaw sweep is more accurate to the real world.

Part of that is going to be influenced by whom you're designing the bikes for. Fabian should ride a frame that does best at very low yaw angles. A triathlete riding 22mph is going to experience higher yaw angles.

 


except for the stem, headset, and front brake?
like, exactly all the things that tend to become proprietary in the superbikes?

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

I have, and I think there is. Anyone got some calipers and a Speed Concept? We can measure this. If it DOESN'T have more frontal area, why is low yaw drag worse on the speed concept?


That may well be the case, and I'm not saying there is anything wrong with that. It is just good to understand that "integrating the front end" isn't always a complete win. Even for the triathlete, who maybe just does sprints in urban area where you go fast and there is usually no wind, for instance.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

I'm a little underwhelmed, as I expected the UCI-illegal thing to actually matter.

One of the Specialized guys in the other thread mentioned that they basically couldn't make the Shiv TT cheaply because of the process used to mold it requires some sort of extra expensive step/part because of the angles and shapes, but the new Shiv (Tri) doesn't have that issue.

So maybe the total result isn't super impressive on the drag end, but it gets equivalent performance for cheaper. $2800 for the frameset puts it in direct competition with the P3 price-wise, so maybe that should be the comparison.

A good point, and this is why I would love to see a yaw sweep of the QuintanaRoo bikes as a second datapoint.

Lets see some evidence of UCI rules holding back drag.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

But it fits any 11/8stem or aerobar and they fasten to the bike just like any other. The closest shop to me in an emergency if I was packing and needed something done deals mostly with kids bikes and similar. They could dissemble/put together this bike with no instructions. No so with the normal Shiv, top Felt, top trek, etc. I don't thing the HS is proprietary, and the front brake is pretty standard and easy to wrench.

Aside from that design goals weren't my opinion, thats what the Specialized rep said on this forum that they were going for. Its valid to argue to that they didn't accomplish their goals, but to say they didn't intend to build the bike I wanted them to and it didn't meet the goals I wanted them to meet. well not so much. If we are going to go down that route, let me be the first to say it sucks as a mtn bike.

Styrrell

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Styrrell

Let me be clear that I think the Shiv-TRI is a very cool bike for many reasons.

There was a lot of excitement about the UCI illegal shapes and how that would make it much faster.

so, maybe UCI illegal shapes can make a bike much faster, but this new shiv is not evidence of that.

or maybe I am being too picky about what "much" is.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Yes, Cervelo's wind tunnel test showed the P4 beating the SC at low yaw angles... A P4 with straight extensions and no spacers, vs. a SC with ski bend extensions and the tallest and longest stem. Had the P4 had ski bend extensions and the SC been sized up one size with a lower stem, it would be interesting to see what the result would have been. If Cervelo performed such a comparison they're certainly not showing us the data. Not to mention that the bar Cervelo used required modification to work with the P4. If Trek had done similar tricks with their tests, a hue and cry would have ensued on ST.

Trek's white paper showed the SC beating the P4 at all yaw angles... is that the truth? The best thing is to look at all the tests, carefully evaluate the setup for each test, and draw a conclusion that takes into consideration competing tests, not any one single test.

Both frames use the same manf process. Their is a very expensive re useable outer mold and then a non reuseable inner mold.

They aleady have a Shiv (UCI legal for TT), and a Shiv nosecone (UCI illegal for TT), Now they came out with a Shiv tri (Uci illegal).

People are asking for a third outer mold to be made Shiv TT non UCI legal. Thats a pretty tiny market and it pretty much would cannabilize sales from bikes they already sell.

Styrrell

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Styrrell

That's the big thing for me (and probably many others). There's no way I can afford an $8k shiny new bike. A $3500 bike that gives the exact same benefits and is supposedly more adjustable? Now just to convince the wife.......

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speedySTATES

Yes, and in Specialized's wind tunnel data it showed the P4 beating the nosecone shiv at low yaw. In Trek's white paper it is very very close at low yaw.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

One thing missing is the integration of the hydration system vs. wind tunnel data with bottles and/or front bar mounted hydration systems. Maybe there will be an aftermarket for nose cones.

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Who Dares...Wins!

The thing I first noticed from the charts was the numbers. 26-41W for the Shivs! For the whole bike!!
There can't be a lot of fat there to trim, so a lot of hard work, and a hard to make bike, saving you a pretty good percentage in drag...... will still end up saving hardly any watts?

yeah to put it in perspective, I think Coggan said that an entire P3C with Zipp wheels, if it took you an hour to do a 40kTT on that

then if you had a 0 drag bike with 0 drag wheels, you would go 5 minute quicker

the latest round of superbikes are about a minute quicker than the P3C - so there are now only 4 minutes available =)

How many of those 4 minutes will the next generation be able to eat into?

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Its a good question, if the Lotus design had been continually refined and developed instead of shelved in the late 90's where would we be now? What if the Softride FasTT design had been given the same R and D as have gone into the double diamond designs? Both those bikes were faster than the P3 level.
If an aerodynamics group had a blank screen and no restrictions, what kind of design would they come up with. All the R and D has gone into UCI legal designs because thats where large companies with the development budgets have chosen to spend.
I am not saying that the non traditional designs are faster, but they just havent had the developement over the last 10 years of the UCI legal bikes.

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